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Transfusions of platelets are appropriate to prevent or control bleeding associated with deficiencies in platelet number or function. A platelet concentrate produced from a unit of whole blood contains, on average, 7.5 X 1010 platelets and should increase the platelet count by 5 to 10 X 109/L (5,000 - 10,000/uL) in a 70 kg recipient. Apheresis platelet concentrates generally contain 3 - 6 X 1011 platelets, depending on local collection practice, and physicians should be cognizant of the doses provided in their community. A pool of 4 - 8 platelet concentrates or a single donor platelet usually is sufficient to provide hemostasis in a thrombocytopenic, bleeding patient. The efficacy of platelet transfusions can be influenced by other conditions in the recipient such as uremia, medications, concomitant coagulation disorders, alloimmunization to HLA, or platelet antigens, infections or splenomegaly.

Platelet concentrate infusions can be administered to patients without further justification
in the following circumstances:

1) Temporary myelosuppression due to chemo-radiotherapy or underlying disease in a stable patient with platelet count less than 10,000/uL.9-12 Patients with temporary myelosuppression due to chemotherapy or underlying disease (e.g. leukemia) may require prophylactic transfusions at levels between 10,000 and 20,000/uL in the presence of fever or minor hemorrhagic signs.

2) Impending surgery or invasive procedures involving the CNS (including eye) , or other critical areas in which microvascular bleeding is harmful and a platelet count of less than 100,000/uL.**

3) Other surgery or invasive procedures where the operative field can be visualized or external pressure can be utilized to maintain hemostasis and a platelet count of less than 50,000/uL.**

2. Prophylactic platelet transfusions generally are not indicated for patients with chronic aplastic anemia or myelodysplastic diseases. Platelet transfusion for symptomatic thrombocytopenia (minor or moderate bleeding) is a more rational approach in such patients.5

3. There is no role for prophylactic platelet transfusion in routine primary open heart surgery.

*Platelet function defect should be documented by template bleeding time greater than two times the upper limit of normal, or greater than 12 minutes, or presumed defect based on medication ingestion, hypothermia, or instrumentation affecting platelet function.

**Platelet counts listed represent maximal levels; procedures have been performed at lower levels without hemorrhage.